UCSF Fresno will coordinate and execute the recruitment, enrollment and data/sample collection for all prospective study cohorts associated with Projects 2 and 3. Details of the data and sample collection are described in the individual project protocols. Study cohorts of the piece-wise natural history (PWNH) design include four age groups, 0-2, 7-9, 15-19 and 19-22 year olds. With the exception of birth data, all study related visits will be conducted at the UCSF Fresno Center for Clinical and Translational Research. The 0-2 cohort will include 220 pregnant women, with maternal data collected during the second trimester (< 22 weeks) and infant data collected at birth, 12 and 24 months post-natal. Pregnant women will be recruited from multiple peri-natal clinics associated with the UCSF Fresno Obstetrics Department. All births associated with these clinics are performed at the UCSF Fresno-affiliated hospital. Community Regional Medical Center. We will also enroll 220 children for the 7-9 year old cohort, 50% of whom will have been previously diagnosed with asthma. During the CHAPS P20 grant period, 300 children (100 with asthma) were successfully enrolled in Project 2 through a partnership between UCSF Fresno (Mr. Tyner) and Fresno Unified School District. Similar recruitment methods will be applied for this new cohort. Data/samples will be collected at two time points: enrollment (visit 1) and 24 months post-enrollment (visit 2). In addition, 100 adolescents (15-19 years) previously enrolled in the above mentioned CHAPS P20 project and 100 young adults (19-22 years) previously enrolled in FACES will be re-contacted and enrolled for a single data/sample collection visit: